The present invention relates to a lens apparatus which moves optical elements such as lenses in an optical axis direction by using a cam barrel.
Such lens apparatuses are often constituted by, as disclosed in Japanese Patent Laid-Open No. 2001-100080, a guide barrel including a guide groove (straight groove) portion extending in the optical axis direction and a cam barrel including plural cam groove portions. Rotation of the cam barrel moves plural optical elements (lenses) via cam followers engaging with the guide groove portion and the cam groove portions.
When forming plural cam groove portions on the cam barrel, using a same processing method for the plural cam groove portions (for example, forming all the cam groove portions so as to penetrate through a circumferential wall of the came barrel) can reduce processing errors, which makes it easy to improve positional accuracy of the optical elements moved by the cam groove portions.
However, forming on the cam barrel multiple cam groove portions having different cam groove shapes for simultaneously moving the optical elements makes distances between mutually adjacent cam groove portions narrow. In this case, if all the cam groove portions are formed so as to penetrate through the circumferential wall of the cam barrel, an external impact applied to the lens apparatus easily deforms the cam groove portions (or the cam barrel), which reduces the positional accuracy of the optical elements.